It doesn't take much either way.

In the key states, if only 1 out of 100 Trump voters went for Hilary, she would have won by a larger margin.

Had she won, we would have been talking about how sanity prevailed, etc.

But the reality is the race was close enough that it doesn't make sense to have a narrative about why either person won. It was close enough that you cannot say this person made a significant difference or not.

If that sounds counterintuitive, think of it this way: List all the reasons you think Hilary failed (and not just external factors - include her own party's shortcomings).

Any one of these being improved could have resulted in a win for her. To single out one entity and blame him is silly. She lost because the race was close and she did not do all she could to win. She didn't lose because one person was spreading fake news.